Remove workaround for grpc bug.
Remove workaround for grpc bug.

The bug existed in GRPC versions < 1.2.1, and we have been using a newer
version in GitLab since April 2017.
https://gitlab.com/gitlab-org/gitlab-ce/commit/e46f67a5123433f132da28770e4027542062fc81

gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab